The collective type switching circuit described in Patent Literature 1 is a circuit driving a MOSFET and an IGBT, which are connected in parallel. The IGBT causes a switching loss because a tail current is generated when the IGBT is turned off. Accordingly, the collective type switching circuit in Patent Literature 1 still drives the MOSFET within a certain period from a moment when the IGBT is turned off, and then drives the MOSFET to turn off lastly.
Recently, a semiconductor with silicon carbide as a main component has been practically used. The SiC has relatively higher dielectric breakdown electric field strength as compared to silicon, a semiconductor such as a MOSFET can be made slimmer so that a lower on-resistance can be achieved as a result and high speed in switching can also be achieved. However, the SiC is relatively more expensive than the silicon, so it is required to miniaturize a semiconductor element with the use of SiC for cost reduction.
The collective type switching element described in Patent Literature 1 has to prevent the element breakdown caused by a large current such as a short current since there is a period in which the MOSFET is only driven. For example, it is required to provide a countermeasure such as stopping a voltage supply to the MOSFET in a situation where the output current of the MOSFET is over a threshold value. Accordingly, it is required to provide a device for detecting a value of the output current. However, in a case where the SiC is used as the configuration element for MOSFET, a device for detecting current has to be arranged as the SiC element as described above. In other words, the element grows in size and it is opposite to the requirement for miniaturizing the element.